1. Field of the Invention
The present invention relates generally to a catalyst and catalytic method for preparing ketones from carboxylic acids and in particular to a catalyst and catalytic method for preparing methyl-benzyl-ketone (MBK).
2. Description of Related Art
It is known that carboxylic acids can be used as precursors for the production of ketones. See e.g., John W. Nicholson, Alan D. Wilson, “The Conversion of Carboxylic Acids to Ketones: A Repeated Discovery,” J. Chem. Educ. 81, 1362 (2004); B. A. Bolotov et al., “Practical Operations in Organic Catalysis,” 143-145 (University of Leningrad Press) (1959) (Russian); K. Veigand, “Experimental Methods in Organic Chemistry,” 484-490 (D. N. Vitkovsky et al. trans., V.N. Velov ed., Foreign Literature Publishers, Moscow, 1953) (Russian). Current processes for the production of ketones from carboxylic acids, such as those processes disclosed in Nicholson, Bolotov, and Veigand using a single-metal metal-oxide catalyst, are generally slow and provide relatively low yields of the desired ketone. In addition, the single-metal metal-oxide catalysts used in current processes tend to lose their catalytic activity after each process cycle and must be replenished. These issues make it difficult for current processes to be used as continuous processes that are commercially viable.
These issues are particularly evident in the current processes for the production of MBK from carboxylic acids. Current processes for the production of MBK are slow, and generally the yield of MBK by known methods tends to be less than 65%. One of the reasons that known methods of MBK production do not give a high yield of MBK production is because di-benzyl-ketone is formed as a by-product substance, which requires additional refinement. The production of di-benzyl-ketone occurs naturally and can reduce the yield of MBK in the current processes to 55% or less. In addition to yield problems, the catalysts used in current methods loose their activity after each cycle of the process and must be replenished. These disadvantages thus make it difficult to use current processes for commercially viable, continuous process MBK production.
A need exists, therefore, for a high-yield catalytic process for producing ketones, particularly MBK from carboxylic acids. A need also exists for a catalyst that does not need to be regenerated or replenished after each production cycle.